The synthesis and properties of tricyclic analogues of S6-methylthioguanine and O6-methylguanine.

The syntheses of novel tricyclic pyrrolo[2,3-d]pyrimidine analogues of O(6)-methylguanine and S(6)-methylthioguanine are described. The crystal structures and pK(a) values of these analogues are reported. In a standard substrate assay with the human repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) only the oxygen-containing analogue displayed activity.

The syntheses and properties of tricyclic pyrrolo[2,3-d]pyrimidine analogues of S6-methylthioguanine and O6-methylguanine.

The syntheses of novel tricyclic pyrrolo[2,3-d]pyrimidine analogues of S6-methylthioguanine are described. The crystal structures and pKa values of these and related O6-methylguanine analogues are reported. All compounds display higher pKa values than O6-methylguanine with the sulfur-containing analogues being the more basic and exhibiting higher stability in aqueous solution.

The syntheses of tricyclic analogues of O6-methylguanine.

The syntheses of the novel pyrrolo[2,3-d]pyrimidine-based heterocycles as tricyclic analogues of O6-methylguanine are described. Compound 5 is a weak inhibitor of human O6-alkylguanine DNA alkyltransferase.